JPH1174557A - Semiconductor light emitting element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably improve light emitting efficiency, reliability and responsibility, by specifying the conductivity type of an active layer (p) type, and setting its carrier concentration within a specified range. SOLUTION: A semiconductor light emitting element has a double hetero structure wherein an active layer 4 is sandwiched by a first conductivity type first clad layer 3 and second clad layer 5. As the conductivity type of the active layer 4 is (p) type, dopant is activated without increasing non-light emitting center concentration, and the carrier concentration can be increased. The light emitting efficiency can be improved by setting the carrier concentration of the p-type active layer 4 higher than 1×10<17> cm<3> , not exceeding 3×10<18> cm<3> . The concentration of a light emitting recombination center is not permitted to vary while electricity is carried, by setting the carrier concentration of the p-type active layer 4 in a range of 2×10<17> to 5×10<17> cm<3> , thereby improving the element reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device using an AlGaInP-based compound semiconductor material and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a semiconductor light emitting device using an AlGaInP-based semiconductor material has been used as a light emitting device for a visible region. The reason is that AlGaInP-based materials can be lattice-matched with a GaAs substrate, and III-
This is because it has a feature that the band gap of the direct transition is the largest among the group V compound semiconductors. Especially,
Since the semiconductor laser and the light emitting diode emit direct transition light in the range of 550 nm to 690 nm, high light emission efficiency can be obtained.

However, in order to use an AlGaInP-based semiconductor light emitting device in a short wavelength region, it is necessary to increase the Al composition of the active layer, and it has been difficult to obtain high luminous efficiency. For this reason, there has been reported a semiconductor light emitting device in which the carrier concentration of the active layer is optimized to improve the luminous efficiency.

For example, Japanese Patent Publication No. 5-72118 discloses an n-conductivity type AlGaIn doped with Si in an active layer.
P-based semiconductor light emitting devices have been reported. This first conventional example aims at reducing the diffusion of the dopant from the p-type cladding layer into the active layer during growth.

However, when the active layer made of an AlGaInP-based material is doped with Si, the diffusion of the dopant from the p-type cladding layer into the active layer during the growth can be reduced, but the n conductive layer is formed by the Si in the active layer. There is a problem in that the light emission efficiency is reduced due to the occurrence of a deep level in the mold, an increase in non-emission centers due to the deep level, and a decrease in the diffusion length of holes as minority carriers.

In order to solve this problem, for example, Japanese Patent Application Laid-Open No. Hei 4-212479 discloses an AlG as shown in FIG.
A light emitting diode using an aInP-based material is described.

This light emitting diode comprises an n-type GaAs substrate 181, an n-type AlGaInP cladding layer 183,
a double heterostructure portion comprising an lGaInP active layer 184 and a p-type AlGaInP cladding layer 185 is provided;
A p-type AlGaAs current diffusion layer 187 is provided thereon. A p-type GaAs contact layer 188 is provided on the center of the p-type AlGaAs current diffusion layer 187, and a p-type electrode 1811 is provided thereon. n-type substrate 18
On one side, an n-type electrode 1810 is provided on the entire surface.

In the second conventional example, the active layer 18
4 is set to a p-type having a carrier concentration of 1 × 10 ¹⁷ cm ⁻³ or less or an n-type having a carrier concentration of 5 × 10 ¹⁶ cm ⁻³ or less.

The reason is that the active layer 184 is made of a p-type having a carrier concentration of 1 × 10 ¹⁷ cm ⁻³ or more, or a carrier concentration of 5 × 10 ¹⁷ cm ^−3.
When doping is performed so as to be an n-type of × 10 ¹⁶ cm ⁻³ or more, a non-emission center is formed and luminous efficiency is reduced. Therefore, it is necessary to limit the carrier concentration of the active layer to this range.

By setting the carrier concentration of the active layer in this manner, the light emitting diode having an emission wavelength of 565 nm (green) with the Al composition ratio x = 0.5 in the active layer has a D
The luminous efficiency at C20 mA is about 0.7%, which is
It is described that a luminous efficiency of 0 times was obtained.

[0011]

However, in recent years, higher brightness has been required in recent years.
Also in the conventional example, there is a problem that the luminous efficiency is insufficient and the luminance is low. The reason may be that although the non-emission center can be reduced by reducing the carrier concentration, the emission recombination center is not increased, so that the emission efficiency cannot be increased.

For example, a light emitting diode having a light emission wavelength of 565 nm (green) has a luminous efficiency of at most about 0.7%, and even a device which is actually molded by adopting a structure for reducing the reactive current requires a luminous intensity of about 1 candela. There is a need for further improvement in luminous efficiency and luminance, not luminance. In the case where the carrier concentration of the active layer is set as in the second conventional example, the light emitting wavelength is 555 nm in the element actually molded by adopting the structure for reducing the reactive current.
(Green) had a luminous intensity of 1 candela, an emission wavelength of 570 nm (yellow green) had an intensity of 3 candela, an emission wavelength of 590 nm (yellow) had an intensity of 7 candela, and an emission wavelength of 610 nm (orange) had an intensity of about 10 candela.

Further, in both the first and second conventional examples, there is a problem that the reliability of the element is not sufficiently obtained.

For example, when the carrier concentration of the active layer is 1 × 10
^When it is as low as about ¹⁷ cm ^{-3, the} radiative recombination lifetime changes due to the carrier concentration of the active layer during energization, and acts as non-radiative recombination. Further, the carrier concentration of the active layer is 1 × 10 ¹⁸ cm ^−3.
If it is high enough, the p-type dopant that has worked as a non-light-emitting center will act as light-emitting recombination, so that the luminous intensity tends to be improved by energization compared to the initial stage. Therefore, it is required to set the carrier concentration in a certain range in order to sufficiently obtain the reliability of the device.

[0015] Further, in a semiconductor light emitting device required for applications such as communication, there is also a problem in response. For example, in the case of an AlGaInP-based material, when the carrier concentration of the active layer is about 1 × 10 ¹⁶ cm ⁻³ , the recombination probability is about 1 × 10 ⁻¹⁰ cm ³ sec ⁻¹ , so that the recombination lifetime due to luminescence recombination is obtained. Is only about 30 nsec, and the response characteristic is accordingly slow. For this reason, there has been a problem in using it for recent high-speed optical communication applications.

The present invention has been made in order to solve the problems of the prior art, and provides a semiconductor light emitting device capable of greatly improving luminous efficiency, reliability and responsiveness, and a method of manufacturing the same. The purpose is to do.

[0017]

According to the present invention, there is provided a semiconductor light-emitting device comprising a double heterostructure having an active layer sandwiched between a first cladding layer of a first conductivity type and a second cladding layer of a second conductivity type on a substrate. Wherein the conductivity type of the active layer is p-type, and the carrier concentration thereof is greater than 1 × 10 ¹⁷ cm ⁻³ and 3 × 10 ¹⁸ cm ⁻³ or less. Is achieved.

The carrier concentration of the active layer is 2 × 10 ¹⁷
It may be not less than 5 cm ^{−3 and not} more than 5 × 10 ¹⁷ cm ⁻³ .

The carrier concentration of the active layer is 5 × 10 ¹⁷
cm ^-3 or more and 2 × 10 ¹⁸ cm ^-3 or less.

When the p-type dopant of the active layer is Zn, M
It may be made of g, Be, Hg, Cd, Si or C.

The active layer is composed of (Al _x Ga _{1 -x} ) _y In _{1 -y} P
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1) based material.

A current diffusion layer having a larger band gap than the active layer may be provided on the double hetero structure.

A pair of electrodes are provided with the substrate, the double heterostructure portion and the current diffusion layer interposed therebetween, and an electrode on the side of the current diffusion layer is on a central portion or a peripheral portion of the current diffusion layer. A current blocking layer having a conductivity type different from that of the current diffusion layer may be provided on the double hetero structure so as to face the electrode on the current diffusion layer side with the current diffusion layer interposed therebetween.

A pair of electrodes are provided with the substrate, the double heterostructure portion and the current diffusion layer interposed therebetween, and an electrode on the side of the current diffusion layer is on a central portion or a peripheral portion of the current diffusion layer. A current blocking layer having a higher resistance than the current diffusion layer may be provided on the double hetero structure so as to face the electrode on the current diffusion layer side with the current diffusion layer interposed therebetween.

According to the method of manufacturing a semiconductor light emitting device of the present invention, the first conductive type first clad layer and the second conductive type second clad layer have a p-type conductivity and a carrier concentration of 1 ×.
A method for manufacturing a semiconductor light-emitting device having a double heterostructure portion sandwiching an active layer having a size of more than 10 ¹⁷ cm ^-3 and 3 × 10 ¹⁸ cm ^-3 or less, comprising a p-type dopant with respect to a supply molar flow rate of a group III material. Of the supply molar flow rate of
The method includes the step of growing the active layer by one or more MOCVD methods, thereby achieving the above object.

Hereinafter, the operation of the present invention will be described.

In the present invention, since the active layer is p-type, the non-emission center concentration increases as in a conventional semiconductor light-emitting device which is made n-type by Si doping as shown in FIG. Without activating the dopant, the carrier concentration can be increased. Further, the carrier concentration of the p-type active layer is larger than 1 × 10 ¹⁷ cm ⁻³ and 3 × 10 ¹⁸
When the ^{density is not} more than cm ⁻³ , the luminous efficiency is improved as shown in FIGS. 2, 6 and 9 described later.

The carrier concentration of the p-type active layer is 2 × 10 ¹⁷ c
Since the concentration of the luminescence recombination center does not fluctuate during energization by setting it to not more than m ^{−3 and not} more than 5 × 10 ¹⁷ cm ⁻³ , the reliability of the element is reduced as shown in FIGS. Be improved.

The carrier concentration of the p-type active layer is 5 × 10 ¹⁷ c
If it is not less than m ^{-3 and not} more than 2 × 10 ¹⁸ cm ^-3 , even if the recombination probability is about 1 × 10 ^-10 cm ³ sec ^-1 , as shown in FIG. 20n life
Since the time is improved to sec to 5 nsec, a sufficient response characteristic as a light emitting diode for optical communication can be obtained. At such a carrier concentration, the non-radiative recombination concentration due to doping does not increase so much, and the luminance does not decrease.

As the p-type dopant of the active layer, Zn,
Any dopant such as Mg, Be, Hg, Cd, Si or C can be used as long as it is a p-type conductive dopant.

As the active layer, (Al _x Ga _{1 -x} ) _y In _{1 -y}
A P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) material can be used.

By providing a current diffusion layer having a band gap larger than that of the active layer on the double hetero structure, the current can be diffused over a wide area and the light emitting area can be expanded, thereby further improving the light emitting efficiency.

When a current blocking layer of a conductivity type different from that of the current spreading layer or a current blocking layer having a higher resistance than the current spreading layer is provided so as to face an electrode on the current spreading layer side with the current spreading layer interposed therebetween, Since the current is led to the diffusion layer where the current blocking layer is not formed, the luminous efficiency is improved. For example, if an electrode is provided on the central portion of the current spreading layer and a current blocking layer is provided so as to face the electrode, current is led to a wide area on the periphery of the active layer, and the light emitting area is expanded. In addition to the improvement, the light extraction efficiency from the peripheral portion, which is the portion where the electrode is not formed, is improved. When an electrode is provided on the periphery of the current diffusion layer and a current blocking layer is provided so as to face the electrode, current is guided to the center of the active layer and current density increases, so that luminous efficiency is improved. At the same time, the light extraction efficiency from the central portion where the electrode is not formed is improved.

In the present invention, MOCVD (Metal
Organic Chemical Vapor D
When the active layer is grown by the deposition method, the ratio of the supply molar flow rate of the p-type dopant to the supply molar flow rate of the group III material is set to 0.001 or more, so that the carrier concentration becomes larger than 1 × 10 ¹⁷ cm ^−3. 3x1
A p-type active layer of 0 ¹⁸ cm ⁻³ or less can be grown. In addition, MBE (Molecular Beam E)
pitxy) method, the carrier concentration is 1 × 10 ¹⁷
The 3 × 10 ¹⁸ cm ^-3 or less of p-type active layer greater than cm ^-3 can be grown.

[0035]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In Embodiment 1, AlGaInP using Zn as a p-type dopant of the active layer is used.
The system compound semiconductor light emitting device will be described.

FIG. 1 is a sectional view of the semiconductor light emitting device of the first embodiment.

This semiconductor light emitting device is a light emitting diode, and n-type GaAs (for example, Si
Buffer layer 2 (concentration: 5 × 10 ¹⁷ cm ⁻³ , thickness: 0.5 μm)
Is provided thereon, and n-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.0, y =
0.5, Si concentration 5 × 10 ¹⁷ cm ^-3 , thickness 1.0 μm)
Clad layer 3, p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.5, y = 0.5,
Zn concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 0.5 μm) Active layer 4
And p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P (0 ≦ x ≦ 1, 0
≦ y ≦ 1, for example, x = 1.0, y = 0.5, Zn concentration 5
(× 10 ¹⁷ cm ⁻³ , thickness: 1.0 μm) A double heterostructure portion composed of the cladding layer 5 is provided. On top of this, p-type GaP (for example, Zn concentration 5 × 10 ¹⁸ cm ⁻³ , thickness 5.0)
μm) A current spreading layer 6 is provided. A p-type electrode 11 is provided on a central portion of the p-type current diffusion layer 6, and the n-type substrate 1
An n-type electrode 10 is provided on the entire surface on the side.

This light emitting diode can be manufactured, for example, as follows.

First, on the n-type GaAs substrate 1, for example, M
The n-type GaAs buffer layer 2 and the n-type (A
l _x Ga _1-x ) _y In _1-y P cladding layer 3, p-type (Al _x G
a _1-x ) _y In _1-y P active layer 4, p-type (Al _x Ga _1-x ) _y I
An n _{1 -y} P cladding layer 5 and a p-type GaP current spreading layer 6 are sequentially grown.

Here, during the growth of the active layer 4, the carrier concentration (Zn concentration) is set to 5 × 10 ¹⁷ cm ^−3.
The growth was performed by setting the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material to 0.2.

Next, a p-type electrode 11 is formed on the central portion of the p-type current diffusion layer 6, and the n-type electrode 10 is formed on the entire surface of the n-type substrate 1.
Is formed, a green light emitting diode having an emission wavelength of 555 nm is completed.

In this embodiment, since the carrier concentration (Zn concentration) of the active layer 4 is set to 5 × 10 ¹⁷ cm ^-3 , the luminous efficiency can be improved. This will be described with reference to FIGS.

FIG. 2 is a graph showing the relationship between the carrier concentration (cm ⁻³ ) of the active layer and the luminous efficiency (%) when the active layer is doped with Zn. As can be seen from this figure, when the Zn concentration of the active layer is greater than 1 × 10 ¹⁷ cm ^{−3 and} less than or equal to 3 × 10 ¹⁸ cm ⁻³ , the luminous efficiency exceeds 1.2%. It can be seen that luminous efficiency approximately twice as high as that of the example semiconductor light emitting device can be obtained.

Here, the reason why the luminous efficiency is increased by doping the active layer with Zn will be described.

FIG. 3 shows that the active layer is doped with Si and n
9 is a graph showing the relationship between the carrier concentration (cm ^-3 ) of the active layer and the non-emission center concentration NT (cm ^-3 ) for a light emitting diode made into a mold and a light emitting diode made into a p-type by doping Zn. As can be seen from the figure, when the active layer is doped with Si to be n-type, when the Si concentration becomes close to 1 × 10 ¹⁷ cm ^−3, a deep level due to Si is generated, and the non-radiative recombination caused by the level is caused. Increase. On the other hand, when the active layer is doped with Zn to be p-type, non-radiative recombination due to generation of a deep level does not increase until the Zn concentration approaches 1 × 10 ¹⁸ cm ^−3. .

Therefore, when the active layer is doped with Si to make it n-type as in the first conventional example, non-radiative recombination due to generation of a deep level increases and luminous efficiency decreases. When the active layer is doped with Zn to be p-type, non-radiative recombination due to generation of a deep level does not increase so much, so that the carrier concentration (Zn concentration) is 1 × 10 ¹⁸ cm ^−3.
It is possible to increase the emission center by increasing it to near,
It is considered that the luminous efficiency can be improved.

Also, as in the second conventional example, the active layer 18
The carrier concentration of 4 is a p-type or 1 × 10 ¹⁷ cm ⁻³ or less or 5
In the case of n-type of × 10 ¹⁶ cm ⁻³ or less, it is considered that the non-radiative recombination center does not increase due to the low carrier concentration, but the luminous efficiency cannot be increased because the luminescent recombination center does not increase.

As shown in FIG. 2, when the carrier concentration of the active layer is higher than 1 × 10 ¹⁸ cm ⁻³ , the luminous efficiency is slightly reduced, but the reason is that the non-luminous centers are greatly increased. It is thought to be.

When the light emitting diode was molded with resin, a green light having a light emission wavelength of 555 nm and a luminous intensity of 2 candela, which was twice the luminous intensity of the conventional one, was obtained.

This is the same even if the Al composition of the active layer is changed, and only the luminous efficiency is increased or decreased.
The composition has the effect of improving the luminous efficiency. For example, p
Type (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦
1) Emission wavelength 570 where Al composition x = 0.4 in active layer
nm yellowish green, luminous intensity 5 candela, Al composition x = 0.3, yellow light emission wavelength 590 nm, luminous intensity 15 candela, A
1. Orange light intensity of 610 nm with a composition x = 0.2 and a light intensity of 20 candela, red light of an emission wavelength of 645 nm with an Al composition x = 0 and a light intensity of 30 candela. was gotten.

In this embodiment, since the carrier concentration (Zn concentration) of the active layer 4 is set to 5 × 10 ¹⁷ cm ^-3 , the reliability can be improved. This will be described with reference to FIG.

FIG. 4 shows a case where the active layer is doped with Zn under the conditions of a driving current of 30 mA and 60 ° C.
5 is a graph showing the relationship between the carrier concentration (cm ⁻³ ) of the active layer and the luminous intensity deterioration rate (%) after the lapse of 00 hours. Here, the luminous intensity degradation rate indicates the ratio of the luminous intensity after lapse of 5000 hours to the initial luminous intensity.
It is assumed that the luminous intensity after lapse of 000 hours is lower than the initial luminous intensity, and that the luminous intensity after lapse of 5000 hours is higher than the initial luminous intensity when the luminous intensity deterioration rate exceeds 100%. As can be seen from this figure, the Zn concentration of the active layer is 2 × 10 ¹⁷ cm ⁻³ or more and 5
In the range of × 10 ¹⁷ cm ⁻³ or less, the luminous intensity deterioration rate is 80%.
It can be seen that the reliability has been greatly improved.

The reason is as follows. That is, when the carrier concentration of the active layer is as low as about 1 × 10 ¹⁷ cm ⁻³ , the light-emitting recombination lifetime changes due to the carrier concentration of the active layer during energization. Show the trend. On the other hand, when the carrier concentration of the active layer is as high as about 1 × 10 ¹⁸ cm ⁻³ , the p-type dopant which has functioned as a non-emission center acts as a radiative recombination. Show. Therefore, the Zn concentration of the active layer is set to 2 × 10 ¹⁷ cm ⁻³ or more and 5 × 10 ¹⁷ cm ^−3.
By setting the following range, the emission recombination lifetime does not change during energization, and the reliability is greatly improved.

This is the same even when the Al composition of the active layer is changed, and has the effect of improving the reliability with all the Al compositions. For example, p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1) Al composition x = 0.
4, yellow-green light emission wavelength of 570 nm, Al composition x =
0.3, emission wavelength of 590 nm, Al composition x =
An orange color with a light emission wavelength of 610 nm set to 0.2, a red light with a light emission wavelength of 645 nm with an Al composition x = 0, and a luminous degradation rate of 80% or more were obtained for all the light emission colors after 5000 hours.

In this embodiment, (Al _x Ga
_1-x ) _y The effect of the present invention could be sufficiently obtained even if the composition ratios x and y of In _1-y P were appropriately changed. This is the same for the following embodiments.

The structure of the semiconductor light emitting device is not limited to the structure shown in the present embodiment, but it is needless to say that the structure can be applied to semiconductor light emitting devices having various structures. This is the same for the following embodiments.

(Embodiment 2) In Embodiment 2, AlGaInP using Mg as a p-type dopant of the active layer is used.
The system compound semiconductor light emitting device will be described.

FIG. 5 is a sectional view of the semiconductor light emitting device of the second embodiment.

This semiconductor light emitting device is a light emitting diode, and n-type GaAs (for example, S
A buffer layer 22 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm is provided, and an n-type (Al _x Ga _{1 -x} ) _y In
_1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.7,
y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) Cladding layer 23, p-type (Al _x Ga _1-x ) _y In _1-y P
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.3, y =
0.5, Mg concentration 3 × 10 ¹⁷ cm ^-3 , thickness 0.5 μm)
Active layer 24 and p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.7, y = 0.5,
(Mg concentration: 5 × 10 ¹⁷ cm ⁻³ , thickness: 1.0 μm) A double heterostructure portion composed of a cladding layer 25 is provided.
On top of this, p-type GaP (eg, Mg concentration 5 × 10 ¹⁸ c
m ⁻³ , thickness 5.0 μm). A p-type electrode 211 is provided on a central portion of the p-type current diffusion layer 26.
Is provided on the entire surface of the n-type substrate 21 side.
Is provided.

This light emitting diode can be manufactured, for example, as follows.

First, an n-type GaAs buffer layer 22, an n-type (Al _x Ga _1-x ) _y In _1-y P clad layer 23, and a p-type (A)
l _x Ga _1-x ) _y In _1-y P active layer 24, p-type (Al _x Ga _1-x )
_1-x ) _y In _1-y P cladding layer 25 and p-type GaP current diffusion layer 26 are sequentially grown.

Here, during the growth of the active layer 24, the ratio of the supply molar flow rate of Mg to the supply molar flow rate of the group III material is set at ^0.1 in order to make the carrier concentration (Mg concentration) 3 × 10 ¹⁷ cm ⁻³ . Growth was set at 1.

Next, on the central portion of the p-type current diffusion layer 26,
The light emitting diode is completed by forming the mold electrode 211 and forming the n-type electrode 210 on the entire surface on the n-type substrate 21 side.

In this embodiment, since the carrier concentration (Mg concentration) of the active layer 24 is set to 3 × 10 ¹⁷ cm ⁻³ , the luminous efficiency can be improved. This will be described with reference to FIG.

FIG. 6 is a graph showing the relationship between the carrier concentration (cm ⁻³ ) of the active layer and the luminous efficiency (%) when the active layer is doped with Mg. As can be seen from this figure, when the Mg concentration in the active layer is more than 1 × 10 ¹⁷ cm ⁻³ and 3 × 10 ¹⁸ cm ⁻³ or less, the luminous efficiency exceeds 1.2%, and the conventional semiconductor light emission It can be seen that luminous efficiency about twice as high as that of the device can be obtained. When the carrier concentration of the active layer is higher than 1 × 10 ¹⁸ cm ⁻³ , the luminous efficiency is slightly reduced. The reason why such luminous efficiency is obtained is the same as in the case where the active layer is doped with Zn.

When the above-mentioned light emitting diode was molded with a resin, a yellow luminous wavelength of 590 nm and a luminous intensity of 15 candela, which was almost twice the luminous intensity of the related art, was obtained.

This is the same even when the Al composition of the active layer is changed.
The composition has the effect of improving the luminous efficiency.

In this embodiment, since the carrier concentration (Mg concentration) of the active layer 4 is set to 3 × 10 ¹⁷ cm ⁻³ , the reliability can be improved. This will be described with reference to FIG.

FIG. 7 shows a case where the active layer is doped with Mg at a driving current of 30 mA and a temperature of 60 ° C.
5 is a graph showing the relationship between the carrier concentration (cm ⁻³ ) of the active layer and the luminous intensity deterioration rate (%) after the lapse of 00 hours. As can be seen from this figure, the Mg concentration in the active layer is 2 × 10 ¹⁷ c
In the range of not less than m ^{-3 and not} more than 5 × 10 ¹⁷ cm ^-3 , the luminous intensity deterioration rate exceeds 80%, which indicates that the reliability has been greatly improved. The reason why the reliability can be improved in this manner is similar to the case where the active layer is doped with Zn.

This is the same even when the Al composition of the active layer is changed, and has the effect of improving the reliability with all the Al compositions.

(Embodiment 3) In Embodiment 3, AlGaInP using Be as a p-type dopant of the active layer is used.
The system compound semiconductor light emitting device will be described.

FIG. 8 is a sectional view of the semiconductor light emitting device of the third embodiment.

This semiconductor light-emitting device is a light-emitting diode, and n-type GaAs (for example, S
A buffer layer 32 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm is provided, and an n-type (Al _x Ga _{1 -x} ) _y In
_1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.7,
y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) Cladding layer 33, p-type (Al _x Ga _1-x ) _y In _1-y P
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 0.05, y =
0.5, Be concentration 1.2 × 10 ¹⁷ cm ^-3 , thickness 0.5μ
m) Active layer 34 and p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 0.7, y =
0.5, Be concentration 5 × 10 ¹⁷ cm ^-3 , thickness 1.0 μm)
A double heterostructure portion including the cladding layer 35 is provided. On top of this, a p-type GaP (for example, a Be concentration of 5 × 10
^A current diffusion layer 36 ( ¹⁸ cm ⁻³ , thickness 5.0 μm) is provided. On the central portion of the p-type current diffusion layer 36, the p-type electrode 3
The n-type electrode 3 is provided on the entire surface of the n-type substrate 31.
10 are provided.

This light emitting diode can be manufactured, for example, as follows.

First, an n-type GaAs buffer layer 32 and an n-type (A
l _x Ga _1-x ) _y In _1-y P cladding layer 33, p-type (Al _x
Ga _1-x ) _y In _1-y P active layer 34, p-type (Al _x G
a _1-x ) _y In _1-y P clad layer 35 and p-type GaP current diffusion layer 36 are sequentially grown.

Here, during the growth of the active layer 34, the ratio of the supply molar flow rate of Be to the supply molar flow rate of the group III material is set so that the carrier concentration (Be concentration) becomes 1.2 × 10 ¹⁷ cm ^−3. Growth was set at 0.008.

Next, the p-type current diffusion layer 36 has
The light emitting diode is completed by forming the mold electrode 311 and forming the n-type electrode 310 on the entire surface on the n-type substrate 31 side.

In the present embodiment, the carrier concentration (Be concentration) of the active layer 34 is set to 1.2 × 10 ¹⁷ cm ^-3 , so that the luminous efficiency can be improved. This will be described with reference to FIG.

FIG. 9 is a graph showing the relationship between the carrier concentration (cm ⁻³ ) of the active layer and the luminous efficiency (%) when the active layer is doped with Be. As can be seen from this figure, when the Be concentration of the active layer is more than 1 × 10 ¹⁷ cm ⁻³ and 3 × 10 ¹⁸ cm ⁻³ or less, the luminous efficiency exceeds 1.2%, and the conventional semiconductor light emission It can be seen that luminous efficiency about twice as high as that of the device can be obtained. The reason why such luminous efficiency is obtained is the same as in the case where the active layer is doped with Zn.

When the light emitting diode was molded with a resin, a red light having a light emission wavelength of 645 nm and a light intensity of 30 candela was obtained.

This is the same even when the Al composition of the active layer is changed.
The composition has the effect of improving the luminous efficiency.

In this embodiment, the carrier concentration (Be concentration) of the active layer 4 is 1.2 × 10 ¹⁷ cm ^-3 , but the Be concentration is 2 × 10 ¹⁷ cm ^-3 or more and 5 × 10 ¹⁷ cm ^{-3. 17}
In the range of cm ⁻³ or less, the reliability can be improved as follows. This will be described with reference to FIG.

FIG. 10 shows the case where the active layer is doped with Be under the conditions of a driving current of 30 mA and 60 ° C.
9 is a graph showing the relationship between the carrier concentration (cm ⁻³ ) of the active layer and the luminous intensity deterioration rate (%) after lapse of 000 hours. As can be seen from this figure, the Be concentration of the active layer is 2 × 10 ¹⁷
In the range of not less than cm ^{−3 and not} more than 5 × 10 ¹⁷ cm ⁻³ , the luminous intensity deterioration rate exceeds 80%, which indicates that the reliability has been greatly improved. The reason why the reliability can be improved in this manner is similar to the case where the active layer is doped with Zn.

This is the same even when the Al composition of the active layer is changed, and has the effect of improving the reliability with all the Al compositions.

In the first to third embodiments, the case where Zn, Mg, and Be are used as the p-type dopant is described. The effects of improving the luminous efficiency and improving the reliability as described in (1) are obtained.
You may use dopants, such as d, Si, and C. This is the same in the following embodiments.

(Embodiment 4) In this embodiment 4, the carrier concentration of the p-type active layer is set to 5 × 10 ¹⁷ cm ⁻³ or more and 2 × 10 ¹⁷
An AlGaInP-based compound semiconductor light emitting device having a size of ¹⁸ cm ⁻³ or less will be described.

FIG. 11 is a sectional view of a semiconductor light emitting device according to the fourth embodiment.

This semiconductor light emitting device is a light emitting diode, and an n-type GaAs (for example, S
A buffer layer 42 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm is provided, and an n-type (Al _x Ga _{1 -x} ) _y In layer is formed thereon.
_1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 1.0,
y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) Cladding layer 43, p-type (Al _x Ga _1-x ) _y In _1-y P
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 0.05, y =
0.5, Zn concentration 2 × 10 ¹⁸ cm ⁻³ , thickness 0.5 μm)
Active layer 44 and p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.0, y = 0.5,
(Zn concentration: 5 × 10 ¹⁷ cm ⁻³ , thickness: 1.0 μm) A double heterostructure portion including a cladding layer 45 is provided.
On top of this, p-type GaP (for example, Zn concentration 5 × 10 ¹⁸ c
m ⁻³ , thickness 5.0 μm). A p-type electrode 411 is provided on the center of the p-type current diffusion layer 46.
Is provided on the entire surface of the n-type substrate 41 side.
Is provided.

This light emitting diode can be manufactured, for example, as follows.

First, an n-type GaAs buffer layer 42, an n-type (Al _x Ga _1-x ) _y In _1-y P cladding layer 43, and a p-type (A)
l _x Ga _1-x ) _y In _1-y P active layer 44, p-type (Al _x Ga _1-x )
_1-x ) _y In _1-y P clad layer 45 and p-type GaP current diffusion layer 46 are sequentially grown.

Here, during the growth of the active layer 44, the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material is set to 2 in order to make the carrier concentration (Zn concentration) 2 × 10 ¹⁸ cm ^−3. Set and grew.

Next, on the central portion of the p-type current diffusion layer 46, p
By forming the mold electrode 411 and forming the n-type electrode 410 on the entire surface of the n-type substrate 41, a red light-emitting diode having an emission wavelength of 645 nm is completed.

In the present embodiment, since the carrier concentration (Zn concentration) of the active layer 44 is 2 × 10 ¹⁸ cm ⁻³ , the luminous efficiency can be improved. As shown in FIG. 2, when the Zn concentration of the active layer is in the range of more than 1 × 10 ¹⁷ cm ⁻³ and 3 × 10 ¹⁸ cm ⁻³ or less, the luminous efficiency becomes 1.2.
%, Which is about 2% lower than that of the conventional semiconductor light emitting device.
Double luminous efficiency can be obtained.

In the present embodiment, the active layer 44
Since the carrier concentration (Zn concentration) is 2 × 10 ¹⁸ cm ⁻³ , the response speed can be greatly improved.
This will be described with reference to FIG.

FIG. 12 is a graph showing the relationship between the carrier concentration (cm ⁻³ ) of the active layer and the rise time (nsec) under the conditions of a drive current of 50 mA and an optical output of 1 mW when the active layer is doped with Zn. It is. As can be seen from this figure, the Zn concentration of the active layer is 5 × 10 ¹⁷ c
In the range of m ^{−3 to} 2 × 10 ¹⁸ cm ⁻³ , the rise time is as fast as 15 nsec or less, indicating that the response speed is greatly improved.

The reason is as follows. That is, even if the recombination probability is about 1 × 10 ¹⁰ cm ³ sec ⁻¹ , the recombination lifetime by luminescence recombination is improved to 20 to 5 nsec due to the increase in the carrier concentration of the active layer. The rise time is improved.

Further, as shown in FIG. 3, if the carrier concentration is at this level, non-radiative recombination due to doping does not increase so much, so that the luminance does not decrease.

In the semiconductor light emitting device of this embodiment,
The response speed can be greatly increased as compared with the conventional semiconductor light emitting device, and a greatly improved response characteristic that can be used for communication applications and the like can be obtained.

This was not changed even when the Al composition of the active layer was changed, and the effect of improving the luminous efficiency and the response speed was obtained with all the Al compositions. Also, p
Mg, Be, H
The effect of improving the luminous efficiency and the response speed was obtained with all the dopants which become p-type conductive, such as g, Cd, Si or C.

(Embodiment 5) In Embodiment 5, an AlGaInP-based semiconductor light emitting device having an n-type current diffusion layer provided at the center between a p-type cladding layer and a p-type current diffusion layer will be described.

FIG. 13 is a sectional view of the semiconductor light emitting device of the fifth embodiment.

This semiconductor light-emitting device is a light-emitting diode, and an n-type GaAs (for example, 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm-thick) buffer layer 122 is provided on an n-type GaAs substrate 121. n-type (Al _x Ga _1-x ) _y
In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) cladding layer 123, p-type (Al _x Ga _{1 -x} ) _y I
n _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.
4, y = 0.5, Zn concentration 1.05 × 10 ¹⁷ cm ⁻³ , thickness 0.5 μm) Active layer 124 and p-type (Al _x Ga _1-x )
_y In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) A double heterostructure portion composed of the cladding layer 125 is provided. An n-type GaP (for example, 0.5 μm thick) current blocking layer 12 is formed on the center of the double heterostructure.
7 over which a p-type GaP (for example, a Zn concentration of 5 × 1) is formed over a portion where the current blocking layer 127 is formed and a portion where the current blocking layer 127 is not formed.
(0 ¹⁸ cm ⁻³ , thickness 5.0 μm). A p-type electrode 1211 is provided on the center of p-type current diffusion layer 126 so as to face current blocking layer 127, and an n-type electrode 1210 is provided on the entire surface of n-type substrate 121.

This light emitting diode can be manufactured, for example, as follows.

First, on the n-type GaAs substrate 121, the first
As a third growth step, the n-type GaAs buffer layer 122 and the n-type (Al _x Ga _{1 -x} ) _y I
n _1-y P cladding layer 123, p-type (Al _x Ga _1-x ) _y In
_1-y P active layer 124, p-type (Al _x Ga _1-x ) _y In _1-y P
N-type G serving as cladding layer 125 and current blocking layer 127
An aP layer is sequentially grown.

Here, during the growth of the active layer 124, the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material is adjusted so that the carrier concentration (Zn concentration) becomes 1.05 × 10 ¹⁷ cm ^−3. Growth was set at 0.004.

Next, an n-type current blocking layer 127 is formed on the central portion of the double heterostructure by etching away the peripheral portion while leaving the central portion of the n-type GaP layer.

Subsequently, as a second growth step, the p-type Ga is formed over a portion where the current blocking layer 127 is formed and a portion where the current blocking layer 127 is not formed.
A P current diffusion layer 126 is grown.

Thereafter, a p-type electrode 1211 is formed on the central portion of the p-type current diffusion layer 126, and an n-type electrode 1210 is formed on the entire surface of the n-type substrate 121, so that the emission wavelength 5
A 70 nm yellow-green light emitting diode is completed.

In this embodiment, the p-type cladding layer 1
N-type Ga in the center between the
Since the P current blocking layer 127 is provided, the p-type electrode 121
The current injected from No. 1 is spread in the p-type current diffusion layer 126 to the periphery where the n-type current blocking layer 127 is not provided. As a result, the active layer 124 that is a light emitting region
Since light emission can be obtained in a wide area, the luminous efficiency can be further improved, and the effect of the first embodiment can be further improved.

When the above light emitting diode was molded with a resin, a yellowish green light having a light emission wavelength of 570 nm and a luminous intensity of 9 candela, which was three times the luminous intensity of the related art, was obtained.

(Embodiment 6) In Embodiment 6, an AlGaInP-based semiconductor light emitting device having a high-resistance current diffusion layer provided at the center between a p-type cladding layer and a p-type current diffusion layer will be described.

FIG. 14 is a sectional view of a semiconductor light emitting device according to the sixth embodiment.

This semiconductor light-emitting device is a light-emitting diode, and an n-type GaAs (for example, Si concentration 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm-thickness) buffer layer 132 is provided on an n-type GaAs substrate 131. n-type (Al _x Ga _1-x ) _y
In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) cladding layer 133, p-type (Al _x Ga _{1 -x} ) _y I
n _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.
4, y = 0.5, Zn concentration 1.5 × 10 ¹⁷ cm ⁻³ , thickness 0.5 μm) Active layer 134 and p-type (Al _x Ga _1-x ) _y
In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
(0 μm) A double heterostructure portion composed of a cladding layer 135 is provided. A high-resistance GaP (for example, 0.5 μm thick) current blocking layer 137 is provided on the central portion of the double heterostructure portion, and a p-type GaP (for example, Zn) is formed over a portion where the current blocking layer 137 is formed and a portion where the current blocking layer is not formed. Concentration 5
(× 10 ¹⁸ cm ⁻³ , thickness 5.0 μm) A current diffusion layer 136 is provided. A p-type electrode 1311 is provided on the center of the p-type current diffusion layer 136 so as to face the current blocking layer 137, and the n-type electrode 131 is formed on the entire surface of the n-type substrate 131.
0 is provided.

This light emitting diode can be manufactured, for example, as follows.

First, on the n-type GaAs substrate 131, the first
As a third growth step, the n-type GaAs buffer layer 132 and the n-type (Al _x Ga _{1 -x} ) _y I
n _1-y P cladding layer 133, p-type (Al _x Ga _1-x ) _y In
_1-y P active layer 134, p-type (Al _x Ga _1-x ) _y In _1-y P
A cladding layer 135 and a high-resistance GaP layer serving as a current blocking layer 137 are sequentially grown.

Here, during the growth of the active layer 134, the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material is adjusted so that the carrier concentration (Zn concentration) becomes 1.5 × 10 ¹⁷ cm ^−3. Growth was performed at 0.005. In addition, the current blocking layer 137 can be set as a high resistance layer regardless of the p and n conductivity types. For example, the current blocking layer 137 can be doped with a low p-type or n-type carrier concentration, or doped with p-type and n-type. It can be grown by co-doping with a type dopant.

Next, a current blocking layer 137 is formed on the central portion of the double hetero structure portion by etching away the peripheral portion while leaving the central portion of the high resistance GaP layer.

Subsequently, as a second growth step, p-type Ga is formed over the portion where the current blocking layer 137 is formed and the portion where the current blocking layer 137 is not formed.
A P current diffusion layer 136 is grown.

Thereafter, a p-type electrode 1311 is formed on the central portion of the p-type current diffusion layer 136, and an n-type electrode 1310 is formed on the entire surface of the n-type substrate 131, so that the emission wavelength is 5 nm.
A 70 nm yellow-green light emitting diode is completed.

In this embodiment, the p-type cladding layer 1
A high resistance G is provided in the central portion between
Since the aP current blocking layer 137 is provided, the p-type electrode 13
The current injected from 11 is spread in the p-type current diffusion layer 136 to the periphery where the high resistance current blocking layer 137 is not provided. Thereby, the active layer 1 which is a light emitting region
Since light emission can be obtained in a wide area of 34, the light emission efficiency can be further improved, and the effect of the first embodiment can be further improved.

When the light emitting diode was molded with a resin, a yellowish green light having a light emission wavelength of 570 nm and a luminous intensity of 9 candela, which was three times the conventional luminous intensity, were obtained as in the sixth embodiment.

(Embodiment 7) In this embodiment 7, an AlGaInP-based semiconductor light emitting device having an n-type current diffusion layer provided at a peripheral portion between a p-type cladding layer and a p-type current diffusion layer will be described.

FIG. 15 is a sectional view of the semiconductor light emitting device of the seventh embodiment.

This semiconductor light-emitting device is a light-emitting diode. An n-type GaAs (for example, Si concentration of 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm thick) buffer layer 142 is provided on an n-type GaAs substrate 141. n-type (Al _x Ga _1-x ) _y
In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) cladding layer 143, p-type (Al _x Ga _{1 -x} ) _y I
n _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.
5, y = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 0.
5 μm) Active layer 144 and p-type (Al _x Ga _1-x ) _y In
_1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 1.0,
y = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) A double heterostructure portion including the cladding layer 145 is provided. N on the periphery of the double heterostructure
-Type GaP (for example, 0.5 μm in thickness) current blocking layer 147 is provided, and p-type GaP (for example, Zn concentration 5 × 10 ¹⁸ ) is formed on the current blocking layer 147 formed portion and non-formed portion.
(cm ⁻³ , thickness 5.0 μm) A current diffusion layer 146 is provided. A p-type electrode 1411 is provided on the periphery of p-type current diffusion layer 146 so as to face current blocking layer 147, and an n-type electrode 1410 is provided on the entire surface of n-type substrate 141.

This light emitting diode can be manufactured, for example, as follows.

First, on the n-type GaAs substrate 141, the first
As the third growth step, for example, the n-type GaAs buffer layer 142 and the n-type (Al _x Ga _{1 -x} ) _y I are formed by MOCVD.
n _1-y P cladding layer 143, p-type (Al _x Ga _1-x ) _y In
_1-y P active layer 144, p-type (Al _x Ga _1-x ) _y In _1-y P
N-type G serving as cladding layer 145 and current blocking layer 147
An aP layer is sequentially grown.

Here, during the growth of the active layer 144, the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material is set to ^0.1 in order to make the carrier concentration (Zn concentration) 5 × 10 ¹⁷ cm ⁻³ . Growth was set at two.

Next, an n-type current blocking layer 147 is formed on the peripheral portion of the double hetero structure portion by etching away the central portion while leaving the peripheral portion of the n-type GaP layer.

Subsequently, as a second growth step, p-type Ga is formed over the portion where the current blocking layer 147 is formed and the portion where the current blocking layer 147 is not formed.
A P current diffusion layer 146 is grown.

Thereafter, a p-type electrode 1411 is formed on the peripheral portion of the p-type current diffusion layer 146, and an n-type electrode 1410 is formed on the entire surface of the n-type substrate 141, so that the emission wavelength is 5 nm.
A 55 nm green light emitting diode is completed.

In this embodiment, the p-type cladding layer 1
45 and the n-type Ga
Since the P current blocking layer 147 is provided, the p-type electrode 141
The current injected from No. 1 concentrates on the central portion of the p-type current diffusion layer 146 where the n-type current blocking layer 147 is not provided. As a result, the current density can be increased in the central portion of the active layer 144, which is the light emitting region, so that the luminous efficiency can be further improved, and the effect of the first embodiment can be further improved.

When the light emitting diode was molded with a resin, a green light having a light emission wavelength of 555 nm and a luminous intensity of 3.5 candela, which was 3.5 times the conventional luminous intensity was obtained.

(Eighth Embodiment) In an eighth embodiment, an AlGaInP-based semiconductor light emitting device in which a high-resistance current diffusion layer is provided at a peripheral portion between a p-type cladding layer and a p-type current diffusion layer will be described.

FIG. 16 is a sectional view of a semiconductor light emitting device according to the eighth embodiment.

This semiconductor light-emitting device is a light-emitting diode. An n-type GaAs (for example, 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm thick) buffer layer 152 is provided on an n-type GaAs substrate 151, and a buffer layer 152 is provided thereon. n-type (Al _x Ga _1-x ) _y
In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) cladding layer 153, p-type (Al _x Ga _{1 -x} ) _y I
n _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.
5, y = 0.5, Zn concentration 2 × 10 ¹⁷ cm ⁻³ , thickness 0.
5 μm) Active layer 154 and p-type (Al _x Ga _1-x ) _y In
_1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 1.0,
y = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) A double heterostructure portion including the cladding layer 155 is provided. A high resistance GaP (for example, 0.5 μm thick) current blocking layer 15 is formed on the periphery of the double heterostructure.
7 over the p-type GaP (for example, a Zn concentration of 5 × 1)
(0 ¹⁸ cm ⁻³ , thickness 5.0 μm) The current diffusion layer 156 is provided. A p-type electrode 1511 is provided on the periphery of the p-type current diffusion layer 136 so as to face the current blocking layer 157, and an n-type electrode 1510 is provided on the entire surface of the n-type substrate 151.

This light emitting diode can be manufactured, for example, as follows.

First, on the n-type GaAs substrate 151, the first
As a third growth step, for example, the n-type GaAs buffer layer 152 and the n-type (Al _x Ga _{1 -x} ) _y I are formed by MOCVD.
n _1-y P cladding layer 153, p-type (Al _x Ga _1-x ) _y In
_1-y P active layer 154, p-type (Al _x Ga _1-x ) _y In _1-y P
A cladding layer 155 and a high-resistance GaP layer serving as a current blocking layer 157 are sequentially grown.

Here, during the growth of the active layer 154, the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material is set to ^0.1 in order to make the carrier concentration (Zn concentration) 2 × 10 ¹⁷ cm ⁻³ . Growth was set at 05. Further, the current blocking layer 157 can be set as a high resistance layer regardless of the p and n conductivity types. For example, the current blocking layer 157 can be doped with a low p-type or n-type carrier concentration, or doped with p-type and n-type. It can be grown by co-doping with a type dopant.

Next, a current blocking layer 157 is formed on the peripheral portion of the double hetero structure portion by etching away the central portion while leaving the peripheral portion of the high resistance GaP layer.

Subsequently, as a second growth step, the p-type Ga is formed over the portion where the current blocking layer 157 is formed and the portion where the current blocking layer 157 is not formed.
A P current diffusion layer 156 is grown.

Thereafter, a p-type electrode 1511 is formed on the periphery of the p-type current diffusion layer 156, and an n-type electrode 1510 is formed on the entire surface of the n-type substrate 151, so that the light emission wavelength is 5 nm.
A 55 nm green light emitting diode is completed.

In this embodiment, the p-type cladding layer 1
Since the high-resistance GaP current blocking layer 157 is provided at the peripheral portion between the P-type electrode 1 and the p-type current diffusion layer 156,
The current injected from 511 is concentrated at the central portion of the p-type current diffusion layer 156 where the high resistance current blocking layer 157 is not provided. Thereby, the active layer 15 which is a light emitting region
Since the current density can be increased at the center of 4,
The luminous efficiency can be further improved, and the effect of the first embodiment can be further improved.

When the light emitting diode was molded with a resin, a green light having a light emission wavelength of 555 nm and a luminous intensity of 3.5 candela, which is 3.5 times the conventional luminous intensity, was obtained as in the seventh embodiment.

(Embodiment 9) In Embodiment 9, an AlGaInP-based semiconductor light emitting device having an n-type current diffusion layer provided at the center between a p-type cladding layer and a p-type current diffusion layer will be described.

FIG. 17 is a sectional view of the semiconductor light emitting device of the ninth embodiment.

This semiconductor light-emitting device is a light-emitting diode, and an n-type GaAs (for example, Si concentration of 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm thick) buffer layer 162 is provided on an n-type GaAs substrate 161. n-type (Al _x Ga _1-x ) _y
In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) cladding layer 163, p-type (Al _x Ga _1-x ) _y I
n _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.
5, y = 0.5, Zn concentration 1 × 10 ¹⁸ cm ⁻³ , thickness 0.
5 μm) Active layer 164 and p-type (Al _x Ga _{1 -x} ) _y In
_1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 1.0,
y = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) A double heterostructure portion including the cladding layer 165 is provided. N on the center of the double heterostructure
A current blocking layer 167 (for example, having a thickness of 0.5 μm) is provided, and a p-type GaP (for example, having a Zn concentration of 5 × 10 ^{18) is} formed over a portion where the current blocking layer 167 is formed and a portion where the current blocking layer is not formed.
(cm ⁻³ , thickness 5.0 μm) A current diffusion layer 166 is provided. A p-type electrode 1611 is provided on the central portion of p-type current diffusion layer 166 so as to face current blocking layer 167, and n-type electrode 1610 is provided on the entire surface of n-type substrate 161.

This light emitting diode can be manufactured, for example, as follows.

First, on the n-type GaAs substrate 161, the first
As a third growth step, for example, the n-type GaAs buffer layer 162 and the n-type (Al _x Ga _{1 -x} ) _y I are formed by MOCVD.
n _1-y P cladding layer 163, p-type (Al _x Ga _1-x ) _y In
_1-y P active layer 164, p-type (Al _x Ga _1-x ) _y In _1-y P
N-type G serving as cladding layer 165 and current blocking layer 167
An aP layer is sequentially grown.

Here, during the growth of the active layer 164, the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material is set to 1 in order to make the carrier concentration (Zn concentration) 1 × 10 ¹⁸ cm ^−3. Set and grew.

Next, an n-type current blocking layer 167 is formed on the central portion of the double heterostructure by etching away the peripheral portion while leaving the central portion of the n-type GaP layer.

Subsequently, as a second growth step, p-type Ga is formed over the portion where the current blocking layer 167 is formed and the portion where the current blocking layer 167 is not formed.
A P current diffusion layer 166 is grown.

Thereafter, a p-type electrode 1611 is formed on the central portion of the p-type current diffusion layer 166, and an n-type electrode 1610 is formed on the entire surface of the n-type substrate 161 to obtain a light emitting wavelength of 5 nm.
A 55 nm green light emitting diode is completed.

In this embodiment, the p-type cladding layer 1
N-type Ga is located at the center between the
Since the P current blocking layer 167 is provided, the p-type electrode 161
The current injected from 1 is spread in the p-type current diffusion layer 166 to the peripheral portion where the n-type current blocking layer 167 is not provided. Thus, the active layer 164 serving as a light emitting region
Since light emission can be obtained in a wide area, the luminous efficiency can be further improved, and the effect of the first embodiment can be further improved. Further, since the carrier concentration of the p-type active layer is set to 1 × 10 ¹⁸ cm ⁻³ , the embodiment 5
The response speed can be further increased as compared with.

When the light emitting diode was molded with a resin, a semiconductor light emitting device having a green light emission wavelength of 555 nm and a luminous intensity of 4 candela, which is four times the conventional luminous intensity, could be manufactured stably.

(Embodiment 10) In this embodiment 10,
An AlGaInP-based semiconductor light emitting device in which an n-type current diffusion layer is provided at a peripheral portion between a p-type cladding layer and a p-type current diffusion layer will be described.

FIG. 18 is a sectional view of the semiconductor light emitting device of the tenth embodiment.

This semiconductor light-emitting device is a light-emitting diode. An n-type GaAs (for example, Si concentration of 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm thick) buffer layer 172 is provided on an n-type GaAs substrate 171. n-type (Al _x Ga _1-x ) _y
In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 1.
0, y = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) cladding layer 173, p-type (Al _x Ga _{1 -x} ) _y I
n _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example, x = 0.
5, y = 0.5, Zn concentration 1 × 10 ¹⁸ cm ⁻³ , thickness 0.
5 μm) Active layer 174 and p-type (Al _x Ga _{1 -x} ) _y In
_1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, for example x = 1.0,
y = 0.5, Zn concentration 1 × 10 ¹⁸ cm ⁻³ , thickness 1.0 μ
m) A double heterostructure portion composed of the cladding layer 175 is provided. N on the periphery of the double heterostructure
-Type GaP (for example, 0.5 μm thick) current blocking layer 177 is provided, and p-type GaP (for example, Zn concentration 5 × 10 ¹⁸ ) is formed on the current blocking layer 177 over the formed portion and the non-formed portion.
(cm ⁻³ , thickness: 5.0 μm) A current diffusion layer 176 is provided. A p-type electrode 1711 is provided on the periphery of p-type current diffusion layer 176 so as to face current blocking layer 177, and n-type electrode 1710 is provided on the entire surface of n-type substrate 171.

This light emitting diode can be manufactured, for example, as follows.

First, on the n-type GaAs substrate 171, the first
As the third growth step, for example, the n-type GaAs buffer layer 172 and the n-type (Al _x Ga _{1 -x} ) _y I are formed by MOCVD.
n _1-y P cladding layer 173, p-type (Al _x Ga _1-x ) _y In
_1-y P active layer 174, p-type (Al _x Ga _1-x ) _y In _1-y P
N-type G serving as cladding layer 175 and current blocking layer 177
An aP layer is sequentially grown.

Here, during the growth of the active layer 174, the ratio of the supply molar flow rate of Zn to the supply molar flow rate of the group III material is set to 1 in order to make the carrier concentration (Zn concentration) 1 × 10 ¹⁸ cm ^−3. Set and grew.

Next, an n-type current blocking layer 177 is formed on the peripheral portion of the double hetero structure portion by etching away the central portion while leaving the peripheral portion of the n-type GaP layer.

Subsequently, as a second growth step, p-type Ga is formed over the portion where the current blocking layer 177 is formed and the portion where the current blocking layer 177 is not formed.
A P current diffusion layer 176 is grown.

Thereafter, a p-type electrode 1711 is formed on the peripheral portion of the p-type current diffusion layer 176, and an n-type electrode 1710 is formed on the entire surface of the n-type substrate 171 so that the emission wavelength is 5 nm.
A 55 nm green light emitting diode is completed.

In this embodiment, the p-type cladding layer 1
The n-type Ga is formed on the periphery between the p-type current diffusion layer 176 and the p-type current diffusion layer 176.
Since the P current blocking layer 177 is provided, the p-type electrode 171 is formed.
The current injected from No. 1 is concentrated in the central portion of the p-type current diffusion layer 176 where the n-type current blocking layer 177 is not provided. Thus, the current density can be increased in the central portion of the active layer 174, which is the light emitting region, so that the luminous efficiency can be further improved, and the effect of the first embodiment can be further improved. Further, since the carrier concentration of the p-type active layer is 1 × 10 ¹⁸ cm ⁻³ , the response speed can be further increased as compared with the seventh embodiment.

When the light emitting diode was molded with a resin, a semiconductor light emitting device having a green light emission wavelength of 555 nm and a luminous intensity of 5 candela, which is 5 times the luminous intensity of the conventional one, could be manufactured stably.

[0167]

As described in detail above, according to the present invention,
By setting the carrier concentration of the p-type active layer to be higher than 1 × 10 ¹⁷ cm ^{−3 and} lower than or equal to 3 × 10 ¹⁸ cm ⁻³ , the luminous efficiency of the semiconductor light emitting device can be improved and the luminance can be greatly improved.

In particular, according to the semiconductor light emitting device of the second aspect, the carrier concentration of the p-type active layer is 2 × 10 ¹⁷ cm ^−3.
Since it is 5 × 10 ¹⁷ cm ⁻³ or less as described above, the luminous efficiency of the semiconductor light emitting device can be improved and the reliability of the device can be significantly improved.

According to the semiconductor light emitting device of the third aspect, the carrier concentration of the p-type active layer is 5 × 10 ¹⁷ cm ^−3.
As described above, the semiconductor light-emitting element can be used for optical communication applications by improving the luminous efficiency of the semiconductor light-emitting element and greatly improving the response characteristics, since it is 2 × 10 ¹⁸ cm ⁻³ or less. Can be.

In the present invention, the luminous efficiency can be further improved by providing a current diffusion layer having a larger band gap than the active layer on the double hetero structure.

Further, a current blocking layer of a conductivity type different from that of the current spreading layer or a current blocking layer having a higher resistance than the current spreading layer is provided so as to face the electrode on the current spreading layer side with the current spreading layer interposed therebetween. In addition, since the current is guided to the portion where the current blocking layer is not formed in the current diffusion layer, the luminous efficiency can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor light emitting device according to a first embodiment.

FIG. 2 shows a case where an active layer is doped with Zn.
5 is a graph showing the relationship between the luminous efficiency and the carrier concentration of the active layer.

FIG. 3 is a graph showing the relationship between the carrier concentration of the active layer and the non-emission center concentration NT when the active layer is doped with Si to be n-type and when Zn is doped to be p-type.

FIG. 4 shows a case where an active layer is doped with Zn.
5 is a graph showing a relationship between a carrier concentration of an active layer and a luminous intensity deterioration rate.

FIG. 5 is a sectional view of a semiconductor light emitting device according to a second embodiment.

FIG. 6 shows a case where an active layer is doped with Mg.
5 is a graph showing the relationship between the luminous efficiency and the carrier concentration of the active layer.

FIG. 7 shows the case where the active layer is doped with Mg.
5 is a graph showing a relationship between a carrier concentration of an active layer and a luminous intensity deterioration rate.

FIG. 8 is a sectional view of a semiconductor light emitting device according to a third embodiment.

FIG. 9 shows the case where the active layer is doped with Be.
5 is a graph showing the relationship between the luminous efficiency and the carrier concentration of the active layer.

FIG. 10 is a graph showing the relationship between the carrier concentration of the active layer and the luminous intensity degradation rate when the active layer is doped with Be.

FIG. 11 is a sectional view of a semiconductor light emitting device according to a fourth embodiment.

FIG. 12 is a graph showing the relationship between the carrier concentration of the active layer and the rise time when Zn is doped into the active layer.

FIG. 13 is a sectional view of a semiconductor light emitting device according to a fifth embodiment.

FIG. 14 is a sectional view of a semiconductor light emitting device according to a sixth embodiment.

FIG. 15 is a sectional view of a semiconductor light emitting device according to a seventh embodiment.

FIG. 16 is a sectional view of a semiconductor light emitting device according to an eighth embodiment.

FIG. 17 is a sectional view of a semiconductor light emitting device according to a ninth embodiment.

FIG. 18 is a sectional view of a semiconductor light emitting device according to a tenth embodiment.

FIG. 19 is a sectional view of a conventional semiconductor light emitting device.

[Explanation of symbols]

1, 21, 31, 41, 121, 131, 141, 15
1, 161, 171 substrate 2, 22, 32, 42, 122, 132, 142, 15
2, 162, 172 buffer layer 3, 23, 33, 43, 123, 133, 143, 15
3, 163, 173 n-type cladding layers 4, 24, 34, 44, 124, 134, 144, 15
4, 164, 174 active layer 5, 25, 35, 45, 125, 135, 145, 15
5, 165, 175p cladding layer 6, 26, 36, 46, 126, 136, 146, 15
6, 166, 176 current diffusion layers 127, 137, 147, 157, 167, 177 current blocking layers 10, 210, 310, 410, 1210, 1310,
1410, 1510, 1610, 1710 n-type electrode 11, 211, 311, 411, 1211, 1311,
1411, 1511, 1611, 1711 p-type electrode

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahashi Kurahashi 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Tetsuro Murakami 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside the corporation

Claims (9)

[Claims] 1. A semiconductor light-emitting device having a double heterostructure portion having an active layer sandwiched between a first cladding layer of a first conductivity type and a second cladding layer of a second conductivity type on a substrate, wherein the active layer is Has a p-type conductivity and a carrier concentration of 1
A semiconductor light emitting device having a size greater than × 10 ¹⁷ cm ^{-3 and} equal to or less than 3 × 10 ¹⁸ cm ^-3 . 2. The carrier concentration of the active layer is 2 × 10
The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device has a size of ¹⁷ cm ⁻³ or more and 5 × 10 ¹⁷ cm ⁻³ or less. 3. The method according to claim 1, wherein the carrier concentration of the active layer is 5 × 10
2. The semiconductor light emitting device according to claim 1, wherein said semiconductor light emitting device has a size of ¹⁷ cm ^-3 or more and 2 × 10 ¹⁸ cm ^-3 or less. 4. The p-type dopant of the active layer is Zn,
2. The method according to claim 1, wherein the material comprises Mg, Be, Hg, Cd, Si or C.
4. The semiconductor light emitting device according to any one of items 1 to 3. 5. The method according to claim 1, wherein the active layer is (Al _x Ga _{1 -x} ) _y In _{1 -y.}
2. A P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) material.
5. The semiconductor light emitting device according to any one of items 1 to 4, 6. The semiconductor light emitting device according to claim 1, wherein a current diffusion layer having a larger band gap than the active layer is provided on the double hetero structure. 7. A pair of electrodes are provided so as to sandwich the substrate, the double heterostructure portion, and the current diffusion layer, and an electrode on the side of the current diffusion layer is on a central portion or a peripheral portion of the current diffusion layer. 7. A current blocking layer having a conductivity type different from that of the current diffusion layer is provided on the double hetero structure portion so as to face an electrode on the current diffusion layer side with the current diffusion layer interposed therebetween. The semiconductor light-emitting device according to claim 1. 8. A pair of electrodes are provided so as to sandwich the substrate, the double heterostructure portion, and the current diffusion layer, and an electrode on the side of the current diffusion layer is on a central portion or a peripheral portion of the current diffusion layer. 7. The current blocking layer according to claim 6, wherein a current blocking layer having a higher resistance than the current diffusion layer is provided on the double hetero structure so as to face the electrode on the current diffusion layer side with the current diffusion layer interposed therebetween. Semiconductor light emitting device. 9. A first cladding layer of the first conductivity type and a second cladding layer of the second conductivity type, wherein the conductivity type is p-type and the carrier concentration is greater than 1 × 10 ¹⁷ cm ⁻³ and 3 ×. 10 ¹⁸ c
A method for manufacturing a semiconductor light emitting device having a double heterostructure portion sandwiching an active layer of m- ³ or less, wherein a ratio of a supply molar flow rate of a p-type dopant to a supply molar flow rate of a group III material is 0.001 or more. A method for manufacturing a semiconductor light emitting device, comprising a step of growing the active layer by MOCVD.